Plain English Meaning
The direction you fly away from a navigation point before turning around to come back to it. It's the 'going out' part of a holding pattern or course reversal.
Full Definition
The published or assigned magnetic course flown away from a navigation fix, station, or waypoint. In holding patterns and procedure turns, the outbound course is the leg flown in the direction opposite the inbound course, used to position the aircraft for the inbound segment back to the fix.
Context Anchor
Seen in instrument procedures such as , procedure turns, and entries, where must fly away from a fix before returning inbound.